title: Microcirculation imaging based on full-range high-speed spectral domain correlation mapping optical coherence tomography.
abstract: Microcirculation imaging is a key parameter for studying the pathophysiological processes of various disease conditions, in both clinical and fundamental research. A full-range spectral-domain correlation mapping optical coherence tomography (cm-OCT) method to obtain a complex-conjugate-free, full-range depth-resolved microcirculation map is presented. The proposed system is based on a high-speed spectrometer at 91 kHz with a modified scanning protocol to achieve higher acquisition speed to render cm-OCT images with high-speed and wide scan range. The mirror image elimination is based on linear phase modulation of B-frames by introducing a slight off-set of the probe beam with respect to the lateral scanning fast mirror's pivot axis. An algorithm that exploits the Hilbert transform to obtain a complex-conjugate-free image in conjunction with the cm-OCT algorithm is used to obtain full-range imaging of microcirculation within tissue beds in vivo. The estimated sensitivity of the system was around 105 dB near the zero-delay line with ∼20  dB roll-off from ±0.5 to ±3  mm imaging-depth position. The estimated axial and lateral resolutions are ∼12 and ∼30   μm, respectively. A direct consequence of this complex conjugate artifact elimination is the enhanced flow imaging sensitivity for deep tissue imaging application by imaging through the most sensitive zero-delay line and doubling the imaging range.
authors.affiliation: National University of Ireland, Tissue Optics and Microcirculation Imaging Facility, National Biophotonics and Imaging Platform, University Road, Galway, Ireland. hrebeshms@gmail.com
authors.forename: Hrebesh M
authors.initials: HM
authors.lastname: Subhash
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Leahy
mesh_terms: D000465:Algorithms; D001783:Blood Flow Velocity; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D008833:Microcirculation / Q000502:physiology*; D019047:Phantoms, Imaging; D012867:Skin / Q000098:blood supply; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*